What is the Best Size Pot to Grow Cannabis? 420 Guide for Beginners

Setting up a cannabis garden is a game of choices. Around every corner, there are decisions that impact the health and prosperity of your cannabis plants. Choosing the right container is one of the more important decisions a grower must make.

Selecting the optimal growing containers for weed isn’t always easy and straight forward. While you may be able to get by with the ol’ flower pot for your first grow, you want to choose the right growing containers, that provide for optimal growth and healthy plants.

If we were to simplify things a bit, the optimal growing containers for your weed plants would be those types of pots, that will provide your plants with the best possible environment for their roots. Healthy roots are essential for optimal nutrition and water intake and quite literally are the foundation for the healthy growth of your plants.

Pick a Pot Size

It is best to keep your cannabis plants in grow pots varying between 1.5 – 3 gallons, 3 gallons being the norm (1 gallon is 3.8 liters). If you have a lot of room in your grow tent then you may even want to consider 5 gallon pots.


What is the reasoning behind this? Well, cannabis plants grow long, winding roots; if they are restricted your roots can become “pot bound”. This simply means that there is not enough room for your roots; they cannot develop fully and thus will not be able to supply your cannabis plants the nutrients to the extent they require – leading to nutrient deficiencies.

Follow these rough guidelines for your desired plant length:

30cm plant (12") - 2-3 gallon pot
60cm plant (24") - 3-5 gallon pot
90cm plant (36") - 5-7 gallon pot
120cm plant (48") - 6-10 gallon pot
150cm plant (60") - 8-10+ gallon pot

Planting a seedling in a pot size correlating to your desired height is not guaranteeing your plant will reach that height. A few things to keep in mind:

Too large of a pot, too soon, and your roots will over expand. Root density is important to ensure your plant is absorbing 100% of what it should be. Too small of a pot and your plant's growth will slow. You should also consider what kind of pot is best suited for your needs.

Transplanting Your Plants Into Bigger Growing Containers

Most of the time (with some exceptions as mentioned above) you will likely start out your seedlings or clones in small containers and transplant them to bigger pots when the right time has come. The reason here is, that a bigger container allows for a larger root system, that your now rather grown-up cannabis plant will require to get all her nutrients.

Transplanting on the other hand can always cause some stress for your plants and if not done carefully, could even kill your plant, say, should you damage the roots when transplanting. It is therefore important, that you move your plants, so that you don’t disrupt their roots in any way.

Finally

Unless you know you cannabis very well, and can gauge exactly how much water each plant needs, it is best to buy a container with holes/perforations in the bottom of it. This will allow any excess water to run out of the container, helping to decrease the chances of root rot – a problem that occurs when soil remains too wet for too long. By placing your containers on trays, you can safely collect any run off and ensure you plants don’t become waterlogged.